It has been found that serious health damage and even death of young children are far from rare by playing of children with containers such as bottles, cans, etc. containing pharmaceutical preparations and then eating sucn preparations, the more so as they often appear to be similar to candy and also by playing with containers filled with liquids or powders as used in households such as detergents, powerful solvents, bleaches, etc. Injuries caused by opening of containers with a potentially harmful content have reached such alarming proportions that a Poison Prevention Packaging Act was enacted in 1970. This Act states that there is a need for providing special packaging to protect children from serious personal injury or illness resulting from handling, using or ingesting household substances which may be toxic, such as medicines, detergents, drain cleaners, etc. As a result of this Act, various types of so-called child-proof closures have been developed and are now in general use. There are three types available -- one type requires exerting and maintaining strong manual pressure in axial direction between a drive member and the closure cap proper to permit opening or closing of the latter; the second type requires the application of powerful radial pressure upon the drive member for squeezing teeth on the closure cap and the drive member into rotation transmitting engagement and a third type requires placement of the drive member into accurate rotational register with the closure cap. While the required axial or radial pressure which must be maintained until the closure cap is screwed off or on, may prevent opening of a container by a young child, it also makes the use of this type of closure device difficult, if not impossible, to use by very many adult persons. Women often have not the necessary physical strength to manipulate closure devices of this type and people whose fingers have lost their dexterity due to arthritic or rheumatic stiffness also will find it difficult if not impossible to open a bottle closed by a child-proof closure device, and just such persons have the need of opening and closing containers filled with drugs which they must use. The type which requires placement of the drive member and the closure cap into exact register is difficult to handle if the light conditions are not very good and for persons who have poor eyesight; usually the markings on the drive member and the closure cap are very tiny and often pale so that they are difficult to see.